DTC (Diagnostic Trouble Code) is the code a vehicle ECU uses to store the faults it detects. DTC Off is the process of removing selected fault codes from the ECU software. At MyEcuFile you can also do this yourself with the DTC Remover tool.
What is a DTC (fault code)?
In modern vehicles the ECU constantly monitors data from sensors and actuators. When a value outside the expected range is detected, it records the relevant fault code (for example P0401, P2002) and, if necessary, turns on the engine warning light in the instrument cluster. Codes help workshops find the fault.
Why are fault codes deleted?
After a fault has been fixed, you may want the code permanently removed from the ECU record. DTC Off is also used when, because of a modification, a sensor has become unnecessary or works differently and produces a false fault.
Fault code groups
Standard OBD-II codes are divided into systems by their first letter:
- P codes: powertrain such as engine, fuel, ignition and transmission
- B codes: body systems (such as air conditioning, doors, seats)
- C codes: chassis systems (such as ABS, suspension, steering)
- U codes: network and communication systems (such as the CAN line)
How is DTC Off done?
The ECU file is read, the definition of the relevant fault code is found in the software and the parameters needed to stop the code being generated are adjusted. The software counterpart of each code differs by ECU model, so the work is done specifically for the file.
The DTC Remover tool
MyEcuFile members can use the DTC Remover tool in the panel to upload ECU files, view the list of fault codes in the file, select the ones they want to delete and download the modified file. The tool shows the session time during the process and keeps a record of completed operations.
The tool works free for a certain number of successful operations per week and charges a credit fee per file after that. The current tariff is shown in the panel.
Step by step with DTC Remover
- Open DTC Remover from the Tools section of the panel
- Upload your ECU file; while the file is read, the ECU information (manufacturer, hardware, software version) is displayed
- Select the codes you want to delete from the list of fault codes in the file; you can search for a code with the search box
- Start the process; the tool shows whether the codes were removed successfully
- Download the modified file and keep a backup of the original file
Difference between DTC Remover and the DTC Off service
DTC Remover is a self-service tool where you pick the codes yourself and modify the file instantly; it is fast and under your control. The DTC Off service is the method where the request is processed by our engineers, better suited to cases not in the list, specific to an ECU or complex.
Things to note
- Deleting a fault code does not fix the fault itself; the cause must be found first
- Before deleting safety-related fault codes, make sure the problem has really been fixed
- Always keep a backup of the original file
- Deleting emission-related codes should be evaluated separately under the regulations of the country concerned
Frequently asked questions
Registered members in the panel. When the tool is enabled on your account it appears in the Tools section of the main menu.
Because the code has been removed from the software, the ECU no longer creates a record for that fault. However, if the physical fault continues, the vehicle's behaviour is still affected by it.
Codes defined and supported in the ECU file are listed. For codes not in the list you can create a special request.
For members a certain number of successful operations per week are free; after that a certain credit amount is deducted for each successful file. The current tariff is shown at the top of the tool.
When the code is removed from the ECU software, no warning is produced for that fault. However, if the underlying physical fault continues, the vehicle's behaviour is still affected; deleting a code does not fix the fault.